Process of making hermetically-sealed conduits.



No. 825,589. 1 A PATENTED JULY 10, 1906.

A. S. DIXON.

PROCESS OF MAKING HERMETICALLY SEALED GONDUITS.

APPLICATION FILED APR.11,1904.

Iggy. :5.

UNITED STATES PATENT OFFICE. I

ALBERT S. DIXON, OF LOS ANGELES, CALIFORNIA, ASSIGNOR TO f AMERICAN CONDUI'I (10., OF LOS ANGELES, CALIFORNIA, A

CORPORATION OF CALIFORNIA.

PROCESS OF MAKING HERMETICALLY-EALED CONDUITS.

Specification of Letters Patent.

Patented July 10, 1906.

Application filed April 11, 1904. Serial No. 202,654.

To all who) if may concern:

Be it known that I, ALBERT S. DIXON, a citizen of the United States, residing at Los Angeles, in the county of Los Angeles and State of (alifoi-nia, have invented certain new and useful Improvements in Processes of Making IIermetically-Sealed Conduits, of which the following is a specification.

This invention relates to an improved process or method of forming hermeticallysealed continuous conduits, and refers more specifically to an improved method of laying and hermetically joining sections of bituminized-fiber conduits.

The salient object of the present invention is to provide a method whereby sections of conduit may be united in such manner as to form a continuous conduit integral and of homogeneous construction throughout to all practical intents and purposes.

Other objects are to provide a method or process which results in producing a hermetically-sealed conduit durable and impervious to both gas and liquids and at the same time possessinginsulatmg qualities of high and permanent character and electrol'sis-proof throughout, including the points 0 union or joints.

To the above ends the invention consists in the im roved process hereinafter de scribed, ant? more particularly pointed out in the appended claims.

I have discovered that bituminized fiber conduit may be hermetically sealed and joined by providing the meeting sections with interfitted male and female joints and then immersing in or ap lying to one or both members of the joint a iot bath of bitumen until the material of the conduit is softened and unites homo eneously with the melted bitumen, and wlnle it is thus softened and coated with bitumen bringing the joint members together into intimate union. In practically carrying out my rocess it is essential that the meeting ends 0 the conduit-sections be so constructed that they telescope together for a substantial distance, the tenon or male member beingconstructed to fit accurately and tightly within the other memher, so that the meeting surfaces willv be joined by a comparativel thin film of material united homogeneous y with the joined members.

- In practically carrying out the process sections of the bitunumzed-fiber conduit are made in suitable lengths and their ends shaped in a suitable lathe, so that the meetplained, are formed by saturating a sheet of tough and high] '-porous fiber board or paper in a bath of melted asphalt or analogous bitum ep product and then while hot and the saturating solution still in liquid form rolling the sheet of material u on a cylindric mandrel until the walls of the conduit-section reach the required thickness, whereupon the conduit-section is removed from the mandrel and allowed to cool and harden. When thus formed-and hardened, the conduit-section is practically homogeneous throughout, and the ends maybe turned off in a suitable lathe to produce the male and female joints re ferred to.

In the following drawings I have shown a variety of'joints'suitable for carrying out my process forming the subject of the present inventlon.

In Figure 1 an ordinary rabbetjoint is shown, rabbets 1 and.2 of the respective sections having end walls 3 'and 4, respectively, formed at rlght angles to the axis of the sections,'and the abutting ends .5 and 6 of the sections being similarly formed at right an gles to the axis of the conduit. The male or tenon member 7 is of suitable external diameter to fit tightly and accurately within the rabbets 2 of the other member.

In Fig. 2 a similar joint is shown, except that the abutting end or edge 8 of the tenon member is rounded and the cob )erating or opposed wall 9 of the receiving-rabbet is correspondingly hollowedfthe parts being, as in the first construction, made to fit accurately throu hout.

In ig'. 3 the tenoned member is provided with an undercut external rabbet 10, having an inclined abuttin wall or shoulder 11, and the cooperating end of the female section is beveled, as indicated at 12, to fit accurately the rabbet 10. j

In Fig. 4 the tenoned member is substantially asthat shown in Fig. 3, while the coopcrating female member has the end Wall or ed e 13 of the telescoping section reversely inc ined, so that when the parts are assembled a triangular space is left between the opposed surfaces 11 and 13, which space is occu ied by the sealing material.

en laying the conduit, I provide a suitable vessel containing melted asphalt or bitumen and means for heating the vessel to maintain the asphalt at a high temperature. Preferably'I employ the same kind of bitumen that is used in originally formingthe sections of conduit. As each section is laid that one of its ends which is to be united to the previously-laid section is dipped into the vessel containing the melted bitumen and held there long enough to become thoroughly 1 heated, slightl softened as to its immersed rately orcedhome allowed to coo surface, and 4 t oroughly and evenl coated with the liquid. The treated end 0 the section is then quickly adjusted into telescoped engagement with the endof the-previouslylaid section and forced into intimate interfitting union with the latter, usually by a slight twistin movement, and after bein aclcl k 1e hot pitch upon the treated end of the conduitsection, together with the heat which has been imparted to the end of the section itself while immersed in the hot bath, act to soften the end of the previously-laid section sufficiently to cause the pitch to unite the parts homogeneously, and a perfect hermeticallysealed joint is thus formed; In other words, the end of the section is so softened that it will either expand or contract to conformto the size and shape of the other member end, Whether it be inserted into or forced over it, whereupon the engaging surfaces of the telescoped ends become welded and incooling are formed into an integral or continuous Such conduits have rified tile, wooden pipe, and more recently socalled v aper pipe composed of bituminized fiber. The latter forms a good non-conductor. Owing to the fact that all such conduits require to be made in short sections presenting numerous joints, unless such jolnts can be made perfectly tight the use of such conduits will not attain complete success. The

chief difficulty encountered has been that the joints, no matter how perfectly formed mechanically, could not be made sufliciently tight to prevent the entrance of liquids and gases or the escape of current when such electrical conduits are laid, as is he uently the case, proximity to gas-pi es.

of gas impregnates the cart surrounding the conduit, and the gas finds ingress, to the interior of the conduit at the joints and passes throu h the same to the manholes ,where the electrical conductors are joined. It is impossible-to prevent sparkingat these joints, and this sparking results in the ignition of the accumulated gas and frequently in violent he leakage explosions, resulting in damage to property and loss of life.

My improvement not only insures liquid and gas tight joints, but it also rovides a perfectly-insulated joint which will'prevent the passage of current and affords a racti-i cally-continuous line of pipe which maintains perfect alinement, thus making it possible to draw the" cable more easily and to use alar er cable.

claim as my invention- The herein-described method of forming a continuous line of iping out of se arate sections composed of bituminized her which consists in providing said sections with male and female joint members constructed to have a substantial telescopic engagement with each other, subinerging one of the'joint members in a bathof hot melted bitumen or bitumen compound, applying the heated and coated end'of the section to the end of the corresponding previously-laid section and forcing the parts tightly together, whereby said sections become hermetically joined and to all intents integral.

ALBERT 's. DIXON.

Witnesses LEE A. McCoxNELL, JOHN S. CRAVENS. 

